Air treatment systems, such as heating, ventilation and air conditioning systems, perform three principal functions in automotive vehicle applications: heating, cooling and dehumidifying the air inside the vehicle. Air thusly treated leads to more even temperature and humidity control, thereby resulting in treated air for passengers to achieve a good level of passenger comfort. Distribution of air, transfer of heat, condensation of water, and maintenance of a closed (air and water tight) system are the steps used to meet these desired effects.
Current HVAC systems for automotive vehicles suffer numerous problems as it relates to ancillary effects of the primary heating, cooling and dehumidifying activities.
One of the chief deficiencies associated with current HVAC functional requirements is the promotion of bacteria, yeast, and fungal growth or development by promoting the ingestion, incubation, and even the continuous distribution of micro-organisms and derived products within the HVAC system and vehicle interior. Contamination of the HVAC system is inevitable, even with the use of filters. The value of filter function is lost when micro-organisms pass through the filter media. The offending organisms include, for example: alternaria alternata, penicillium cyclopium, trichoderma harzianum, bacillus subtilis, bacillus licheniformis, bacillus cereus, acinobacter calcoaceticus, pseudomonas fluorescens, proteus hauseri, staphyloccus epidermis, which generally are too small in size and too prevalent to employ traditionally economical solutions or methods to avoid their entry or distribution to or within the HVAC system.
HVAC systems often are described as working in fresh air or ‘recirculation’ modes. In both fresh air and recirculation mode, micro-organisms are drawn into the HVAC unit. Contamination of the HVAC unit components, including interior surfaces and duct work, necessarily takes place on a continuous basis because the air to be circulated and/or the circulated air is not sterile. Heat transfer, combined with the condensation of water, provides an environment perfectly suited for organism growth. Engine coolant, circulating through most vehicle heater cores while the engine is running, also transfers heat through the core providing a source of warmth. The presence of water vapor, in the form of relative humidity or condensate carryover, for example, can lead to an HVAC functional environment where maintenance, development and/or the growth of micro-organisms, (as well as a medium for such maintenance, development or growth) is created and even propagated. These conditions are, additionally, being maintained in a system that is generally as air and water tight as possible, with, preferably, only the intended entry and exit open. The HVAC functional environment is, therefore, basically a ‘closed’ system that will not function at an optional level if other openings are added (or interruptions are made) along the air flow surface.
U.S. Pat. No. 5,788,930 issued in Aug. 4, 1998, McMurray ‘Apparatus for Purifying an Environment Using Ozone Generation’, addresses the issue of safe and efficient purification of an enclosure, including buildings or vehicles” but does not anticipate the functional requirements of vehicle HVAC systems, and focuses on “efficient purification” in the control of ozone concentrations.
U.S. Pat. No. 5,648,046 issued in Jul. 15, 1997, Weibel ‘Method and System For disinfecting Air In Air Conditioning Ducts,’ describes a method for disinfecting air in ventilation ducts by the use and application of a vaporized ammonia solution that is ionized and distributed within a set of grounded duct work; ionized vapor migrates to the interior walls of the duct due to the ‘grounding effect’, thereby reducing bacteria and mold growth by utilizing the bactericidal properties of ammonia. This reference does not disclose, suggest or anticipate such an application within a vehicle HVAC system.
U.S. Pat. No. 3,750,556 issued in Aug. 7, 1973, Douglas Roy Duke et al ‘Air Purifying Means,’ relates to an “apparatus for conditioning the air being circulated through a confined space”. It does not disclose, suggest or anticipate the HVAC system as a primary source of contamination and would be an ineffective means of addressing the herein described HVAC specific problems, such as the growth or development (‘contamination’) of microorganisms on an evaporator.
U.S. Pat. No. 5,810,896 issued Sep. 22, 1998, Clemens, ‘Air filtration and purification system for vehicle,’ discloses an air filtration and purification system for the interior of a closed vehicle, more particularly, a system mounted in the interior of a closed vehicle wherein polluants are prevented from influxing from outside the vehicle.
U.S. Pat. No. 5,938,523 issued Aug. 17, 1999, Khelifa et al, ‘Device for removing the noxious and aromatic substance from an air flow fed into the interior of a vehicle,’ discloses an absorbent containing device to absorb noxious and aromatic matter.
U.S. Pat. No. 5,942,026 issued Aug. 24, 1999, Erlichman et al, ‘Ozone generators useful in automobiles,’ described inlet air ionization structures useful to produce ozone of the inlet of an internal combustion engine. Column 3 describes ozone in the interior of the filter housing, and that ozone assists in flame propagation inside the combustion chamber.
U.S. Pat. No. 5,762,665 issued Jun. 9, 1998, Abrahamian et al, ‘Vehicular air purification system,’ discloses a vehicle air purification system having specific outlet vents. In column 5, its plurality of components include active and passive filter units.
U.S. Pat. 4,658,707 issued Apr. 21, 1987, Hawkins et al, ‘Automatic air purifier for vehicles’ describes an air purifier which can be positioned within various places in a confined space such as a vehicle interior where smoke may be present' to purify the air therein. It further describes an air filter for filtering tobacco smoke and other airborne impurities.
U.S. patent Publication 2002/0176809 A1, Siess, Nov. 28, 2002, describes a method and apparatus for securing the comfort and health of human beings by the production and maintenance of conditioned air, with, for example, as shown in FIG. 1 of Siess, an air handling device such as those used to condition transportation vehicles that can ‘clean’ air to the cargo holds of a locomotive box car, light and heavy duty delivery trucks and other commercial vehicles, and describes that a similar concept could be used in the ventilation system for conditioning of the air throughout a building or wherein airborne pollutants are generated, such as, but not limited to, copier rooms, computer rooms, bathrooms, operating rooms or zones or rooms having a legislatively mandated level of high air purity. It, therefore, does not anticipate the level of air purification and not just cleaning or filtering, required in a true passenger inhabited space of a passenger vehicle, and, in fact, since it is a filtering system, suggests that its concept is fit even for retrofitting into an existing ventilation systems to clean the air, not the HVAC unit. It also describes no regulation of oxidant levels in an HVAC temperature control chamber, and does not include an oxidant sensor in the passenger compartment.
The Siess disclosure involves a chemical reaction taking place in the encapsulation chamber while the passenger is in the vehicle. There appears to be no amount of component rearrangement, control means, sensor, timer or switch additions that can be made to allow this reaction to occur outside the encapsulation chamber during vehicle operation with a human or animal occupying space in the passenger compartment. In addition, the goal of Siess appears to require the movement of polluted outside air through the device into the passenger environment, thereby not addressing the need for dealing with contaminated air when operating in recirculation mode.
U.S. Pat. No. 5,820,828, Ferone, Oct. 13, 1998, describes a modular ozone distributing system for producing and distributing ozone to an air duct network of a building.
Neither Siess nor Ferone have foreseen the problem or solution of the HVAC system itself as being a primary or secondary source of air pollution. Therefore, the inlet appears to effect on a stream of air and move the stream into a space outside of the unit. The present invention is intended to impact the space within the unit itself, and, unlike the prior art, allows for selective operation when a passenger is not in the vehicle.